Radiant Barrier Performance Insulation Underlay For Carpets & Wood Flooring

Therma-Lay is a revolutionary Performance Radiant Barrier Insulation material developed for use under domestic and contract carpets, natural and sisal floor-coverings, and wood/laminate floorings. It incorporates state-of-the-art technology in design and manufacture. It acts as an all-in-one radiant/vapour barrier, air infiltration barrier and powerful thermal insulation medium that also serves as a static eliminator, and is covered by a pending patent.


Therma-Lay enhances appearance retention, provides wear protection, improved underfoot comfort, reduced noise and most important thermal insulation – (thus reducing problems associated with movement in hard-wood flooring).


Its unique composite design consists of a foldable insulation material which encloses air inside airtight compartments. Surrounded by a thin layer of very strong reinforced metallised surface which is protected against oxidation. It is inorganic, water-resistant, termite and fungus resistant, non-allergenic and extremely light in weight. As the heat capacity is so small, the metallised surface immediately takes over the temperature of the air flowing by.

A well insulated floor promotes a comfortable, healthy lifestyle and conserves energy. The better a floor is insulated the warmer the floor surface stays, preventing that awful feeling of cold feet. Even with a lower air temperature a well insulated floor gives a much greater sense of warmth and comfort and saves on energy.

Therma-Lay is designed to reflect over 80% of the radiant heat waves that strikes its surfaces. By reflecting the radiant waves, the foil surface remains relatively cool, leaving very little heat to be absorbed and conducted through to the ground under the carpet or through the various composites in hard wood flooring. Its unique reinforced construction provides exceptional dimensional stability.

Therma-Lay has been developed to reduce noise transfer in both single and multi-story buildings. reducing noise in both direction, ie. noise traveling down through the floor and up through the ceiling (where the underlay is laid). It is effective for airborne and impact noise, offers an excellent support to all types of carpet, and can reduce sound transfer when laid over a timber floor.


  • SUPER EFFICIENT... Reflects heat energy back into the room.

  • RADIANT/VAPOUR BARRIER... Reflects cold back into the ground and insulates floor-covering

  • DURABLE... Thermal performance will not degenerate over time.

  • CONSISTENT PERFORMANCE... Not effected by moisture and humidity.

  • SUPER-SAFE TO HANDLE... No special handling or breathing protection required.

  • PEACE OF MIND... No health concerns for the homeowner, now or ever!

  • EASY TO INSTALL... Lightweight, cuts and staples easily can be sealed at joins.

  • TOUGH... tear-resistant.

  • ECONOMICAL... inexpensive to install, long lasting.

Therma-Lay is easy to install -- its thin, pliable, lightweight design provides very effective under-floor insulation. It can be laid under carpet, hardwood/parquet, fibre board and vinyl flooring and offers increased energy efficiency over traditional insulation products. Standard width is 1.5 metre wide rolls which can be easily trimmed with a utility knife or pair of scissors to fit any shape or area. Therma-Lays lightweight design also makes it easy on a building's design load. Joins can be easily sealed using Therma-Foil Self Adhesive Performance Tape.

Therma-Lay Can Reduce Dust Mites in Your Home

A warm floor is drier reducing the likelihood of mould and or wood rot. The presence of house dust mites (which can cause Asthma) in floor coverings reduces significantly when the floor is properly insulated, as has been scientifically proven by the University for Agriculture in Wageningen, The Netherlands). Research now indicates that omitting floor insulation also increases the number of house dust mites in the carpet. The assumption that in a home the mattress is the most significant hotbed for mites is no longer valid.

The average allergen concentration in the mattresses is 5088 ng/g, the average allergen concentration in carpets on un-insulated floors in houses with double glazing is 6503 ng/g. The researcher of 512 houses concluded that "Floor insulation can result in a significant reduction of the allergen concentration of dust on carpeted floors".

In this research the average allergen concentration in the carpet on insulated floors is measured by a U-value of 0.60 W/sq.mK. The University advised that with good floor insulation (U-value below 0.30) the allergen concentration will drop well below 2000 ng/g. This is the limit value proposed by the World Health Organisation. It is presently accepted, that exceeding this limit value can cause sensitisation to house mites. It is to be expected that floor insulation will postpone the moment of sensitisation, and in many cases even prevent sensitisation from occurring.

Therma-Lay Reduces Energy/Heating Costs

Saving energy is becoming more and more of an environmental issue. One of the most important fields of saving energy is insulating ones home. Floor insulation should be included when insulating a house or office, especially when double glazing is in use, which without floor insulation causes increased moisture in the area near to the floor. Heat is lost through floors primarily by radiation. Therma-Lay prevents heat rays from penetrating down, reflecting the heat back into the building, thereby warming the floor surfaces. As Therma-Lay is non-permeable, it is unaffected by ground vapours. In double-glazed rooms, a large part of the moisture which used to condense on the single glass window, is now absorbed by an un-insulated floor, which has become the coldest place in the room for most of the time. It has been proven that double glazing can increase the possibility of mould in the carpet, movement within the layers of composite and hard-wood flooring, in furniture and along skirting-boards when floor insulation has been omitted.

The shift of moisture problems from the windows to the floor is best illustrated by comparing the inside temperatures before and after insulation. It is obvious that double glazing is warmer than single glass and therefore increases the time that an un-insulated floor is the coldest surface in the house from 24% to 76% of the time (for the Dutch climate). A well insulated floor (U-value <0.3 W/sq.m K) is so much warmer that it will, almost all of the time, be the warmest surface.

Preventing Wood Rot & Movement in Hard Wood Flooring & Joists using Therma-Lay Performance Insulation material

It is not common knowledge yet that traditional insulation material in a ventilated basement attracts moisture that can damage a wooden floor. This can even happen in basements that initially appear perfectly dry. The problem is caused by the low temperature of the bottom of the insulation material. In summertime warm humid air enters the basement from outside and cools down against the cold insulation material, building up condensation. Moisture vaporising from the soil aggravates the problem. Insulation on top of the floor is no solution because the same phenomenon occurs here as well. Because of the decrease in heat flow, the underside of the flooring panels/planks gets colder and condensation can occur. Therma-Lay provides insulation and remains dry even on warm, humid summer days. The outside air does not cool down so condensation does not take place at all.

Available in 6mm & 8mm Thickness

Note: We endeavor to ensure that any advice, recommendation or information we may give in is accurate and correct. However, we have no control over the circumstances in which our product is used. It is important that end users satisfy themselves by prior testing that the product is suitable for their specific application and that the actual conditions of use are suitable. No responsibility can be accepted or any warranty given by ourselves, other than that the product supplied by us will meet our written specification. Products are sold subject to our standard conditions of sale and each purchaser and end user should at all times be satisfied that the product meets your requirements.

Any of the above information is subject to change in part or as a whole without notice E & OE.

Further information on our extensive range of materials can be obtained by contacting our sales team

Therma-Float,P O Box 8, Beech Lane House, Wilmslow, Cheshire SK9 5ES England

Telephone +44 (0)1625 251000

Fax +44 (0)1625 524584

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